Direct Determination of Volatile Elements in Nickel Alloys by Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry

Abstract

A method is described for the direct determination of Bi, Pb and Te in solid Ni alloys by ETV-ICP-MS. Samples are introduced into the graphite tube as small filings or chips weighing up to 3 mg. Using diluted sea water as a physical carrier, both Bi and Pb could be determined in solid Ni using external calibration with aqueous samples although results for Pb were biased low. Better results in terms of accuracy and precision were obtained when solid RMs (Ni) were used for calibration. LODs of 14 and 44 ng g ^-1 were obtained for Bi and Pb, respectively, using a reduced sensitivity mode (OmniRange). Based on signals obtained for solution standards measured at the highest sensitivity, LODs of 0.002 and 0.004 ng g ^-1 are possible for Bi and Pb, respectively. The determination of Te by this technique was not successful using either solution or solids calibration. Tellurium did not show a linear instrument response with concentration, which was probably due to an interaction between the Te and one or more matrix components in the solid phase that alters the release mechanism(s) for Te from those observed for Pb and Bi.